The Hidden Blade Assassin's Creed in Depth

This article is a continuation from Part 1:
http://www.thehiddenblade.com/marco-barbarigo-assassination-variety-pack

Marco is blind.
Marco Barbarigo is basically an animated game prop. He is oblivious to just about everything. I can find only 3 things that will make him run:

1) Detection of Ezio by any guard, anywhere.
2) Ezio standing on the center or starboard sections of the deck.
3) A gunshot that does not kill Marco.

You can easily swim around and drown the guard on the portside of the ship by pulling him over. After you pull yourself on deck, you can remain undetected as long as you stay near the portside rail. From here, you can wait for Marco to come to you. After he finishes his speech, he will start to walk around in a simple pattern. Wait for him to approach, and then you can have your way with him. You can quietly kill him with the hidden blade or poison blade. You can also punch, headbutt, knee, throw, etc. Personal injury does not cause him to flee. If you take a break from beating him, he will continue walking around the ship as if nothing happened.

Point blank
You won't have many opportunities to shoot your target like this.

The Sniper, Part II
You need to be within 15 m of the target to be able to lock onto him. Once you are locked on, you can move as far as 30 m away, and you'll be able to maintain that lock. The only difficulty is that the camera angle will remain on the target as you walk around, which makes it harder to see where you are going. When you reach the roof of the building, guards will not be able to see you, but they can still hear the gunshot. Dive into the water for an easy escape. If you like, climb back to shore to watch people fleeing from the party.

To the best of my knowledge, there is no way to shoot Marco in a fashion that would ordinarily invoke a response from guards, but it fails to do so due to timing the shot with the explosions. This contradicts the advice of Teodora at the beginning of the mission on how to remain undetected.

The Other Brother
In case you missed it, there is an optional eavesdropping "mission" in the corner of the courtyard. You can listen to the conversation at any time, but I recommend waiting for a quiet moment without interfering dialog, so that you can hear what they are saying.